Make sample code working

Change:
- two bad indentations,
- one unwanted ],
- missing URIRef import.
Missing )
Correct error in sample codes

- invalid indentation,
- unwanted :.
Better to show subject instead of object

We are searching persons. It's better to display:
    http://example.org/people/Bob is a person
than
    http://xmlns.com/foaf/0.1/Person is a person
Method is subjects(), not subject()
Bad indentation in sample code
Merge pull request #334 from PuckCh/master

Some more changes in the doc samples